Building integrated photovoltaic conversion system implemented in both vision and spandrel areas

ABSTRACT

A power generating system is manufactured, integrated and operated within an exterior shell or façade of a building structure. The system components—energy generating devices (which can be photovoltaic), control units and associated power/signal wiring are incorporated and operated within individual unitized curtain wall units making up the façade including both in vision and spandrel areas.

RELATED APPLICATION DATA

The present application claims priority to and is a continuation ofapplication Ser. No. 12/564,686, now U.S. Pat. No. 7,845,127, which inturn claims the benefit under 35 U.S.C. §119(e) of the priority date ofProvisional Application Ser. No. 61/099,437 filed Sep. 23, 2008 andProvisional Application Ser. No. 61/114,410 filed Nov. 13, 2008, allwhich are hereby incorporated by reference. The present application isfurther related to and is a continuation of the following additionalapplications, all of which are incorporated by reference herein:

-   Building Integrated Power Generating System; Ser. No. 12/564,609;-   UL Compliant Building Integrated Photovoltaic Conversion System;    Ser. No. 12/564,627 now U.S. Pat. No. 7,845,126;-   Method of Operating Building Integrated Photovoltaic Conversion    System; Ser. No. 12/564,664;-   Building Integrated Photovoltaic Conversion System Implemented With    Integrated Control Management Units; Ser. No. 12/564,671 now U.S.    Pat. No. 7,847,181;-   Unitized Curtain Wall Module Adapted for Integrated Photovoltaic    Conversion Module; Ser. No. 12/564,732;-   Unitized Building Integrated Photovoltaic Conversion Module; Ser.    No. 12/564,740 now U.S. Pat. No. 7,845,128;-   Unitized Building Integrated Photovoltaic Conversion Module Adapted    With Electrical Isolation and Grounding; Ser. No. 12/564,748;-   Unitized Building Integrated Photovoltaic Conversion Module Adapted    With Electrical Conduits; Ser. No. 12/564,761;-   Integrated Electrical Conduit for Solar PV System; Ser. No.    12/564,768;-   Electrical Raceway for Building Integrated Solar PV System; Ser. No.    12/564,774;-   Method of Assembling Building Integrated Photovoltaic Conversion    System; Ser. No. 12/564,783.

FIELD OF THE INVENTION

The present invention relates to power generating systems integratedwithin building façade or exterior shell structures, and morespecifically to BIPV systems which include both vision area and spandrelarea coverage.

BACKGROUND

It has been long been considered desirable to integrate photovoltaic (orPV) devices and systems into commercial and residential buildings. Todate, however, such systems have been generally limited to conventionalroof-top based systems which have limited photovoltaic capability andlittle aesthetic appeal. Conventional roof-top based systems are limitedin photovoltaic capability because, among other reasons, the moduleswhich make up these conventional systems are connected in series whicheffectively lowers the productivity of the entire system to that of theleast productive of the modules. Conventional roof-top based systemsalso depend upon racking systems which do not afford a practical methodto integrate photovoltaic elements into a vertical building face in anattractive and safe manner. Shading by building elements, equipment, andother constraints severely limit the area available for PV deployment.

Clearly it would be desirable to incorporate PV devices in a larger areaof a building structure, and in a more visually appealing fashion. In arecent attempt at such an endeavor, a building in New York Cityincorporated PV elements in vertical façade assemblies that wereactually physically separate from the main structure, and configured asartistic elements. The project was in fact a failure due to theinability of the system designer to overcome regulatory restrictions onthe incorporation of electrical elements into this type of structure.Thus, while the panels are still attached to the side of the building,they have not been utilized to generate useful PV power.

“Unitized” curtain wall systems are those which can be preassembled andglazed as units (i.e., the glass or other surface material installed)off site and progressively installed section by section on a building.One advantage of the unitized curtain wall approach is that the labor isperformed in an off site, controlled, manufacturing environment.Unitized systems are suitable for mid to large projects, i.e. high-risebuildings (four stories or more), those with significant repetition oftheir components, and/or projects in locations that have higher seismicdesign requirements. Frame units for unitized curtain walls aretypically configured as one module (glazing or glass unit) wide by onestory in height. These pre-glazed frames are typically placed on bunksconsisting of about 6 units each and hoisted by a tower crane to theirrespective floors where they are installed, often by utilizing a smallmobile hoist from the floor above.

The unitized curtain wall systems also typically include a pressureequalized rain screen, which counteracts the forces that cause waterinfiltration, such as surface tension, capillary action, gravity,kinetic energy, and pressure differential. Unitized curtain wall systemsare in wide spread use and gaining commercial popularity across for thecountry because of their ease of integration, reasonable cost,schedule-friendly capabilities and aesthetic beauty and highperformance.

Photovoltaic modular panels have been integrated into curtain wall glassfor building integrated photovoltaics, as seen in U.S. PublicationSerial No. 2008/0163918 incorporated by reference herein. Nonethelessthe design described is optimized only for amorphous type solar cells,and is not conducive to ease of construction because it is notconfigured for efficient inter-modular connection. Nor does such designcompensate for shading, a problem that severely impairs the performanceof conventional series-connected solar panels particularly inarticulated applications like building enclosures. As is well known, inconventional PV approaches shading degrades the performance and poweroutput (or yield) of the shaded module or unit. When shading falls onone or more of the conventional series-connected solar panels, theseries connected modules degrade in overall performance to that of thelowest yield in the string. Finally the prior art also fails to addressthe lack of overall Underwriters Laboratory certification or ULapproval. UL certification of the framing system is an essential elementto enable PV projects to be approved under applicable building andsafety regulations, and thus is a key element to enable widespreadadoption. Many commercially available modules are UL Approved to UL1703, but no framing systems related to Building IntegratedPhotovoltaics (UL Category QHZQ) are commercially available today

WO 2006/123335 incorporated by reference herein suffers from similardeficiencies, in that inter-module connections (in particular thosebetween each individual solar module and those adjacent left and right)are depicted in great detail. However, this system is connected inseries, without individual module management. In addition, the arrayconstruction method lacks inter-module conduits or passages suitable forrouting wiring. Moreover, the modules are connected to each other onlyin a lateral (left and right) fashion; there is no teaching of verticalconnection. For this reason any vertical connections must beaccommodated through additional structures, such as tracks, tubes orstrips that are not integrated into the curtain wall framing members.U.S. Pat. No. 6,646,196 incorporated by reference herein shows a similarset up, and suffers similar deficiencies. These additional runs add costand complexity to installation, reduce operational efficiency, raisemaintenance costs and complexity, and potentially increasesusceptibility to failure.

SUMMARY OF THE INVENTION

An object of the present invention, therefore, is to reduce and/orovercome the aforementioned limitations of the prior art.

A first aspect of the invention concerns a building integrated powergenerating system;

Another aspect of the invention concerns a building integrated powergenerating system that is UL/regulatory compliant;

A further aspect concerns integrating control management units into suchpower generating system;

Yet another aspect concerns a building integrated power generatingsystem that is implemented in both vision and spandrel areas of abuilding façade;

Other aspects include unitized curtain wall units that are adapted forphotovoltaic energy conversion modules;

Still other aspects cover electrical isolation, electrical conduits andgrounding features of such unitized curtain wall units and associatedbuilding integrated power generating systems;

Another aspect of the invention covers integrated wireways/raceways usedwith the unitized curtain wall units;

Further aspects concern methods of assembling/manufacturing suchunitized curtain wall units and building integrated photovoltaicconversion systems;

Other aspects include methods of operating the conversion modules, thecontrol modules, and an entire power generating array integrated withina building shell;

Finally, other aspects of the inventions will be apparent to thoseskilled in the art from the detailed disclosure that follows.

It will be understood from the Detailed Description that the inventionscan be implemented in a multitude of different embodiments. Furthermore,it will be readily appreciated by skilled artisans that such differentembodiments will likely include only one or more of the aforementionedaspects or objects of the present inventions. Thus, the absence of oneor more of such characteristics in any particular embodiment should notbe construed as limiting the scope of the present inventions. Whiledescribed in the context of a power generating array within a buildingfaçade, it will be apparent to those skilled in the art that the presentteachings could be used in any number of applications.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a preferred embodiment of a photovoltaicpower generating system implemented within an exterior shell or façadeof a building structure;

FIG. 2 shows a cutaway section of the building structure along thedirection shown in FIG. 1 designated with a bubble and the numericnotation 2, to illustrate further details and the spatial relationshipof components of the preferred solar power generating system;

FIG. 3 shows a cutaway section of the building structure along thedirection shown in FIG. 1 designated with a bubble and the numericnotation 3, to illustrate further details and the spatial relationshipof components of the preferred solar power generating system;

FIG. 4 shows a cutaway section of the building structure along thedirection shown in FIG. 1 designated with a bubble and the numericnotation 4, to illustrate further details and the spatial relationshipof components of the preferred solar power generating system;

FIG. 5 shows a cutaway section of the building structure along thedirection shown in FIG. 1 designated with a bubble and the numericnotation 5, to illustrate further details and the spatial relationshipof components of the preferred solar power generating system;

FIG. 6 is a block diagram of the main electrical components employed inthe preferred solar power generating system;

FIG. 7 is a flowchart depicting a preferred process used to assembleembodiments of the solar power generating system;

FIGS. 8A and 8B show another perspective of the curtain wall units alongthe direction shown in FIG. 1 designated with a bubble and the numericnotation 8, to illustrate further details and the spatial relationshipof components of the preferred solar power generating system.

DETAILED DESCRIPTION

The present invention preferably incorporates mono and/or poly siliconcrystalline cells used for converting solar energy into electricalenergy, such as those offered by Suntech Power Holdings Co. Ltd.(Suntech) directly into standardized curtain wall products, such asthose offered by Architectural Glass and Aluminum Co, Inc (AGA) ofAlameda Calif. The AGA curtain wall products are well-known durableexterior façades. The end result is a solar power generation system thatalso, much in the same manner as conventional curtain wall, functionallyand aesthetically encloses a building.

By incorporating solar energy directly in the construction process for abuilding, the cost of implementing such green capability is greatlyreduced. The cost of operating such buildings also goes downdramatically as a result of net energy savings by reducing the need forlighting using Daylighting Techniques and by controlling the solar heatgain and envelope U-value to reduce the energy needed for heating,ventilation and air-conditioning systems (HVAC).

The invention also has applicability, however, toretrofitting/re-cladding existing buildings to include solar capability,particularly when such structures include mechanical screeningsurrounding their rooftop. The invention can be used in such instancesto both beautify and increase the functionality of such otherwiseunaesthetic and nonfunctional architectural features.

Unitized Curtain Walls

Before delving into the specifics of the present invention, it is usefulto describe and understand the characteristics of unitized curtainwalls. Unitized curtain walls are an extremely popular form of buildingfaçade used throughout the world.

The main defining characteristic of unitized curtain walls are that theyare substantially (and usually entirely) preassembled off site in unitsand, after transport to the project site, hung or fastened onto on thebuilding's structural slab edges. The unitized curtain wall does nottypically function as a structural support element for the building. Thefinal installation of these pre-assembled units into the integratedwhole results in a “unitized” curtain wall system.

Off-site pre-assembly of the units is far preferable to onsite becauseoperations can be done far more efficiently—at a dedicated facility byskilled personnel—with much lower cost and with higher speed andthroughput. Off-site assembly also leads to higher quality work withbetter seals, stronger bonds, and fewer errors, and further enablesassembly bench testing prior to transportation and installation.

In contrast conventional stick built curtain wall systems require thatthe aluminum or metal frames for the glazing be field-assembled at thejobsite according to the specific architectural requirement. The laborfor such solutions is costly, and the quality of such an installation isdifficult to control from one unit to the next. Moreover, because stickbuilt curtain wall frames are not manufactured in a controlled factoryenvironment, before they can be UL certified, they must be fieldinspected, one by one, for approval. Such one by one field inspection isless preferable than the present invention, because the one by oneapproach consumes longer time and runs the risk that inspection, evenafter the expense of transport and assembly on site, will fail to resultin certification. Prior building integrated PV curtain walls, such asthat mentioned in New York City above, suffered these very failures.Unlike stick built approaches, curtain wall unitized panels aretypically prefabricated as standardized 4′-8′ width×10′-15′ height unitsmade up of different cladding materials (stone, painted aluminum, glass,opaque-glass, etc.) depending on the desired aesthetic/look theArchitect is trying to achieve. A common form factor is five feet wideby thirteen and a half feet tall. The shop pre-assembly of the differentmaterials into a unit, among other things, allows for:

-   -   better quality control of the finished product (both the units        themselves and the overall curtain wall system) and,    -   easy (and thus rapid) installation on site, as each unitized        panel ‘mates’ with the one above, with the one below and with        the ones to either side of it, thereby adding support, and        achieving continuity and integrity for the overall wall once        completed.    -   Decreased duration on job site, thus leading to improved and        more efficient construction schedules    -   minimized packaging because the unitized pre-assembled units may        be transported to the site with less packaging and waste than        stick built, thus promoting environmental goals for reducing and        recycling of jobsite packaging.

A unitized curtain wall unit is typically made up of the following majorparts/components:

-   -   Framing Members: these capture and support the different        cladding or glazing materials desired and frame them into a unit        which is manageable and conveniently sized for final        installation. The framing is typically rectangular (although        other shapes could be used) with vertical framing elements and        horizontal framing elements. Framing members may be comprised of        any materials known in the art, including, aluminum, steel,        fiberglass or other composite materials. The vertical framing        elements (sometimes called ‘mullions’), of each unit ‘mates’        with the units adjacent, thereby providing support to the        adjacent units and achieving continuity of the wall system once        completely installed. The primary horizontal framing elements        (sometimes called the ‘stack joints’) at the top and bottom of        the unit also mate with the units above and below, similarly        providing support to the adjacent unit and the entire wall and        achieving continuity of the wall system once completely        installed. Preferably, each unitized curtain wall unit also        includes one or more intermediate horizontal members. These        intermediate horizontal members are typically used to hold or        mount and provide support to pieces of glazing or cladding. For        example, the glazing below might be transparent or vision glass,        while that above might be PV material. In unitized curtain wall,        these framing members are pre-assembled in the factory. The        pre-assembled frame thus forms the skeleton of the unit which        will, after completion of the pre-assembly as described below,        be transported to the building site for installation.    -   Support Structure/Brackets: are used to fix/connect each of the        curtain wall units to the edge of the building's floor-slab. In        addition to providing the structural support for the wall, these        brackets provide the ability to take up variation in the        building's construction (typically +/−2 to 4 inches) and exactly        align each of the units with one another (typically within +/−⅛        to ¼ of an inch) to achieve the continuity required and the        aesthetic alignment desired. Typically, the support        structures/brackets are composed of two mating components. One        of these is pre-assembled into the unitized frame at the        factory. The other mating component of the support        structure/brackets is typically fastened to the building's        floor-slab onsite. In this manner, the installation on site can        be achieved with convenient attachment of the mating components.    -   Sealant/Gaskets: physically connect and isolate the cladding or        glazing materials to the framing members. The sealant/gaskets        effectively affix the cladding materials to the framing members,        providing a waterproof seal. The sealant/gasket material is        typically semi-flexible to accommodate minor movement of the        frame relative to the cladding material. This isolation of        movement is particularly important for PV, glass, or stone as        they can break due to their brittle nature, but also important        with other thin, opaque materials due to their tendency to        buckle producing an undesirable aesthetic. In the building        integrated PV application, it is preferable to incorporate UL        approved materials designed specifically for this purpose to        assure System UL Compliance. In the building integrated PV        application, the sealants and gaskets also serve to electrically        insulate PV from framing in many applications. The sealant and        gaskets are pre-assembled to the frames and glazing as part of        the pre-assembly.    -   Glazing or Cladding: the material which forms the aesthetic and        structural exterior of the final unitized curtain wall.        Different cladding materials (stone, painted aluminum, glass,        opaque-glass, etc.) may be utilized depending on the desired        aesthetic/look. The glazing or cladding is attached to the        unitized curtain wall frame members during pre-assembly.    -   Vision Material: the transparent glazed area of the unit located        in the zone(s) through which occupants view out or through which        daylight is to be admitted to the building interior. This zone        is typically the entire width of the curtain wall        unit/panel×18″-40″ above the floor to the underside of the        ceiling. The vision material is also pre-assembled into the unit        in the factory.    -   Spandrel Area: In a building with more than one floor the term        spandrel is also used to indicate the space between the top of        the window in one story and the sill of the window in the story        above. The term is typically employed when there is a sculpted        panel or other decorative element in this space, or when the        space between the windows is filled with opaque or translucent        glass, in this case called spandrel glass. Further, many opaque        or translucent materials can be used, including any of a number        of form factors of energy conversion devices. The glazing or        cladding for the spandrel area is attached to the unitized        curtain wall frame members during pre-assembly.

It will be understood by those skilled in the art that this is asimplified description, and not intended to be an exhaustive list. Thecomponents may vary from those described. Moreover not every curtainwall unit will require such components, and some units may in fact useother components without deviating from the spirit of the presentteachings and techniques.

The labor and assembly process associated with curtain wall units isalso divided into separate phases which allows for more optimizedcosting associated with the various activities and better predictabilityof scheduling.

Fabrication Labor: typically includes all the labor involved in makingor cutting/shaping each of the constituent framing and support parts ofthe curtain wall unit and then pre-assembling all the parts into thepre-assembled units designed for installation at the particular project.Since the curtain wall units are assembled typically in a dedicatedfacility, consistency and quality can be better controlled andoptimized.

Installation Labor: typically includes the labor involved in attachingthe support brackets/structures to the building, laying out, hoisting,and hanging the curtain wall units on the building, mating and aligningall the units and taking up tolerances, completing the necessaryelectrical connections, adding final seals, insulation and any interiorfinish trim that needs to be coordinated with finish material (likeceilings or sheetrock) that are typically provided by others. Becausethe on-site assembly method of the unitized curtain wall units iseffectively identical and because all of the units have a common methodfor mating and attachment, the skill sets of the assemblers can bestandardized and more easily controlled as well.

Unitized PV Curtain Walls

The present invention aims to enable unitized curtain wall systems todeliver energy production capability—more specifically photovoltaicfunctionality similar to a rooftop PV installation. That is, a systemthat primarily functions to generate electricity from solar power oncethe entire set of parts are assembled, and also performs the sameaesthetic cladding function as prior art curtain wall systems. Thedifference here, of course, is that the power generation must be ascompatible as possible with the requirements of a PV curtain wall unit,including resistance and compliance with various regulations concerningheat/conductive/insulation properties, air/water infiltration, wind loadresistance and seismic considerations.

To accomplish this, a photovoltaic (PV) curtain wall unit includes thefollowing (in addition to some or all of the standard components notedearlier):

Photovoltaic Panels: for a wall-system application, these are preferablyglazable PV panels—and so can be thought of as a direct materialreplacement for the opaque glazed spandrel and/or vision material in thecurtain wall unit—although there are some differences between thesematerials that are accommodated/designed for as shown in the presentembodiments. Other types of panels/energy conversion devices can ofcourse be used, and in this respect the invention is effectivelypanel-device agnostic. Varying cell density, photovoltaic materials,opacity, and aesthetic look can be adjusted as needed to meet thedesired appearance, aesthetics and requirements.

Inverters/module management units/controls: these typically convert andoptimize electricity generated by PV panels into grid compliant power.Preferably, the inverters/module management units/controls are providedlocally and individually, at each curtain wall unit, to allow the PVwall system to more efficiently generate electricity from solar power.As mentioned, there is frequently greater variability in light exposurefrom one portion of a vertical building surface to another than there ison a typical rooftop installation. As a result, for BIPV applications,it is preferable that local controls account for self or site shading ofeach individual wall unit/panel and eliminate or reduce the otherwisetypical impact from shading in which one shaded unit/module degrades theperformance of the entire string of modules in the affected series.Shading can result from shadows cast by trees, other buildings, dustaccumulation, and even birds, planes, and window cleaners. Theseconditions occur frequently on vertical curtain wall environments, andit is therefore important that the integrated PV curtain wall systeminclude necessary controls and methods to mitigate and/or avoid thisdeleterious impact. In addition, these inverter/control elements shouldbe easily accessible for maintenance and yet preferably be hidden fromview of the occupants of the space as well as from viewers of thebuilding exterior for both safety and aesthetic purposes. Finally, itpreferable that of the above components should be rated UL orequivalent, and outdoor rated to accommodate for building constructionconditions.

Wiring: wiring is preferably accommodated to carry power (and preferablycontrol signals, where necessary) all the way from the PV panels to thegrid without adding additional architectural complexity. Ideally, thewiring will be effectively invisible in the installation condition. Inthe preferred embodiment means are provided from each PV panel, throughthe curtain wall unit, to transport the generated electricity in a safeand controlled way through the entire wall array and ultimately to theinterior of the building. Similar to the needs of the localinverter/controls, the wiring in a curtain wall system should preferablybe done efficiently (i.e., preferably few wires for a long array runhelps limit the size of the code required raceway (or other requiredwiring passage)), in an aesthetically pleasing manner (which, in acurtain wall system typically means hidden from view) while beingprotected from damage and accessible for maintenance. It will beappreciated that in other power generating applications involving otherenergy conversion devices, other types of tubing/conduits, etc., can beemployed to transport other energy related materials, includingheated/cooled fluids, etc. between modules and other parts of acirculation system within a building structure.

Accordingly, unlike previous applications of PV technology on a verticalwall, each PV curtain wall unit of the present invention can be sold,delivered and installed as a complete unit. Each PV curtain wall unit ispreferably preassembled off site and transported to the building as aprefabricated module, allowing this new application to not only besimply, quickly hung on the building, but also, as panels, wiring,inverters and controls have also been prefabricated into a series ofconnected code-rated raceways attached to or formed by the unit framing,each unit can be simply, quickly and efficiently connected, coupled orplugged as needed into its neighboring units.

In an electrical generation system each unit is preferably linked to acommon grounding mechanism using methods well known in the art.

As described above, one main purpose of the invention is to provide aphotovoltaic power from a unitized curtain wall system. The unitsassembled according to the teaching of the invention will preferably beconnected or linked in a manner that accumulates the electricitygenerated by each unit in the manner described above. The electricity soaccumulated is connected to the building's primary electrical system andgrid tied as appropriate, using methods known in the art. It is possiblethat the electricity in the system may be harnessed to run existingmechanical systems within the building envelope such as shading devices,window treatments, or blinds. This implementation thus allows a solarenergy system to be installed as part of a building façade with the sameease and minimal additional labor cost.

Specific Details of Preferred Embodiment

In a conventional rooftop system, PV panels, wiring, controls,rack/support, etc. are all assembled on site and then plugged into theinverter/storage mechanisms. In the case of a preferred unitized PVcurtain wall as described herein the PV curtain wall units arepreferably each ‘plug and play’—each unit mates into and is electricallycoupled to its adjacent unit to form the solar array. In turn, the solararray is electrically connected into the balance of the buildingelectrical system. In this respect therefore, the inventions betterachieve the functionality of a conventional rooftop system, but do so onthe vertical sides of the building. Because a typical high rise buildinghas 7-12 times greater wall than rooftop space, the present inventionallows far greater harvest of solar energy.

In a preferred embodiment the invention is used preferably in claddingat least a substantial vertical portion of a building structure 100 asseen in a partial elevation drawing in FIG. 1. The degree to which PVand non-PV curtain wall units are included and interconnected within acladding can be tailored as needed for any particular site requirementsand system goals. Please note that the elements shown in the figure arenot intended to denote specific sizes or ratios, as it expected that theinvention will take many different forms, sizes, and form factors indifferent types of installations. Moreover although the discussionherein is presented primarily in the context of a commercial structure,it is expected that embodiments can be used on virtually any other typeor variety of structures, including residential structures, parkingstructures, other non-habitable structures, hospitals, airportterminals, train station terminals, sea port terminals, governmentbuildings and even within transportation systems such as elevated rails,bridges, and other structures offering suitable solar exposure.Furthermore while shown as part of an exterior of the building, thecladding could be extended to other interior areas of a structure aswell, such as may be found in an atrium, a courtyard, etc.

A preferred unitized curtain wall structure covering a building facadeincludes a number of separate curtain wall elements 105 preferablyconstituted of aluminum, although it will be understood that othersuitable materials may be used, such as steel, fiberglass, or othercomposite materials. In this instance the curtain wall structure isshown as a combination of vision areas and spandrel areas, but it willappreciated that these could be separate components or utilized invarying combinations. The curtain wall units 105 can be configured asdesired to extend across multiple stories in a continuous strip ofspandrel and vision areas. While the elements 105 are shown as separatecomponents it will be appreciated that larger “units” in the form ofmultiple curtain wall elements could be assembled off-site in someinstances.

The curtain wall elements 105 are further adapted to preferably includea photovoltaic (PV) module 120 and/or other energy conversion device.Such devices could include capability for converting other forms ofelectromagnetic energy, potential energy, kinetic energy, thermal energyand/or chemical energy including photochemical energy. For example,thermionic, piezoelectric and/or mechanical devices could be integratedfor harnessing heat/wind/rain energy). Other examples will be apparentto those skilled in the art, and it is expected that other conversiondevices will be adapted for use with the present invention. Because oftheir physical structure the curtain wall elements 105 can be easilyadapted (mechanically/physically) to house/integrate different types ofsuch conversion devices (which tend to be smaller than such elements)using the principles set out herein. It will be understood that theconversion devices can be spatially arranged as part of the curtain wallelements in any convenient fashion appropriate for the particularinstallation. Furthermore as shown in FIG. 1, it is possible that someelements 105 may include conversion devices, while others may not, againdepending on system requirements and goals.

In addition, in some instances well-known solar thermal energycollectors/plates could be embedded instead or in addition within thecurtain wall elements for heating a conductible fluid, air or some othermedium for transporting heat energy. Other well-known solar thermalsupport elements such as mirrors, lenses and other concentrators (notshown) could be used of course to increase the heat concentration, andconventional heat storage devices (not shown) can be incorporated tostore heat energy.

The PV module used in the preferred embodiment can be any one of avariety of virtually any commercially available PV module, includingpreferably a crystalline solar cell/module offered by Suntech Power. ThePV module can include any number of conveniently and conventionallyinterconnected individual solar cell devices, such as described in theaforementioned prior art references. As is known in the art, thephotovoltaic technology utilized by the PV module may be based on anysuitable photovoltaic conversion technology, including for example, thinfilm, dye tinted, fullerene based, polycrystalline, or monocrystalline.The specifics of the solar cell/module (or other energy conversiondevice) are not material to the present invention; however regardless oftheir specific photovoltaic conversion technology the PV modules must besuitable to physically integrate them within the unitized curtain wallunits. Accordingly, a wide variety of existing and contemplatedtechnologies can be accommodated, thus making the invention PV module“agnostic,” which further enhances the commercial potential for theinvention.

Conventional vision material or, in this case, glass panels 115 are alsoshown in FIG. 1. As described, these glass panels can be configured tohave more than one panel along the vertical axis of the unit. In thisconfiguration, the glass panels will be separated by intermediatehorizontal framing members. Further, while the PV module 120 is shown inFIG. 1 in the vision area of the building structure 100, it canalternatively be integrated into spandrel areas or as part of a spandrelbased module 110, or in any number of combinations of such areas basedon system requirements and design aesthetics.

A linked solar array or assembly of PV curtain wall elements 105, 105′,105″ etc. is thus shown mated together, cladding or enclosing astructure, preferably extending both horizontally and vertically acrossmultiple floors. The elements 105 are preferably sized to be compatiblewith conventional building elements to further increase theirintegration potential. This arrangement is also useful for increasingthe overall solar energy potential coverage for up to nearly 100% of thewall area of a structure. In contrast, typical rooftop systems onlyallow for a limited percentage of an overall surface area.

FIG. 2 shows a cutaway section of the building structure 100 along thevertical axis/direction shown in FIG. 1 designated with a bubble and thenumeric notation 2. In this figure the structure of the curtain wallunits (such as 105, 105′ and 105″ which are otherwise identical) isfurther elaborated, including the relationship of the BIPV module 110 tothe other components. In general, the typical components of curtain wallframing members on a BIPV curtain wall unit 105″ are largely the same inconcept as conventional curtain wall framing members. However there arespecific and significant differences that allow PV Panels to be used inplace of other conventional infill material as explained below.

Specifically, as seen in FIG. 2, the PV module 110 (located in aspandrel area as depicted in FIG. 1) is preferably mounted within anextra deep glazing pocket 125 shown generally with cross hatching foremphasis. The extra deep glazing pocket 125 is preferably part of atopmost horizontal framing member 150 in the spandrel area. This framingmember 150 is also distinct from conventional designs in that itpreferably allows extra space in the glazing pocket 125 for an edgemounted junction box for the PV module 110 and the PV Leads 140 thatcome out of the PV module.

The framing members of the preferred embodiment are unique in that theyform both vertical and horizontal conduits/channels for inter-moduleconnectivity, including preferably, power lines, control signal lines,and reporting lines. In some applications as noted earlier it may bedesirable to transport other fluids, gasses, etc. to and between modulesusing appropriate channels. Further, in some applications the desiredcontrol and reporting information flowing to and from the PV module 110may be transported using wiring or wireless technology, thus obviatingthe need for the separate control signal and reporting lines.

The curtain wall units 105 are engineered using conventional techniquesso that they are adequately resistant to water, pressure and otherphysical influences that might be attendant to a particular locale.Those skilled in the art will appreciate that the specific physicalimplementation can be varied from site to site in accordance with localbuilding code, geological and weather based parameters.

Framing member 150 further preferably includes an opening allowing thePV leads 140 (or other flexible conduit/piping for transportingfluids/gasses) to be routed to a management module or control circuit135 preferably situated in a power/control raceway 130. Again, to theextent other types of materials are transported, the opening can bevaried accordingly.

Power/control raceway 130 is preferably attached to the solar arrayafter installation of the curtain wall units on the building using anyof the techniques known in the art. Nonetheless it can be preassembledas well in some instances. The management module 135 is preferably aunit designed for individual and group control of PV modules such assold by TIGO Energy under the name Energy™ Module Maximizer-EP (MM-EP)and/or modules as described in US Patent Publication Nos. 20080097655and 20090120485 incorporated by reference herein. There are many otherpower topologies accommodated, including but not limited to, Enphase,Solar Edge, Solar Magic, or Enecsys. The management module can be usedto selectively monitor, troubleshoot, activate or de-activate portionsof a building's solar array system, including on a side by side, floorby floor, or individual basis such as might be needed for accommodatingwindow cleaning or maintenance as examples.

The management module is part of a control circuit that preferablyoptimizes power output of each module that it is connected to, anddelivers module-level data for operational management and performancemonitoring and/or control. The TIGO unit in particular uses dynamicmodule balancing which manages the energy harvest and sends informationfor reporting and control. The modules can be connected in a variety ofknown methods, depending on system needs.

The benefits of such module specific control/transmission/communicationwithin a building structure is that they allow for greater efficiency inpower collection and more effective elimination of prior art lossescaused by shading by other external elements (trees, other buildings,dirt, etc.) and inherent mismatches in PV modules. These problems haveheretofore greatly limited efficiencies of solar arrays in horizontal,vertical, or inclined configurations, particularly in densely builtareas. Furthermore since such management modules 135 are UL rated to UL1741, they can be used in preferred embodiments of the invention inwhich an entire solar array for a building is effectively compliant asconstructed with UL (and other safety organization, such as CanadianStandards Association (CSA), InterTec North America (ETL), Tuv Rheinlan(TUV)) requirements because it consists of elements which are eachpreviously certified.

The other advantage of the preferred TIGO management module is theimproved safety of the solar array during operation. In particular,during an emergency, for example, the high voltage wiring in thepreferred embodiment can be shut off, thus preventing accumulation ofvoltage and limiting voltage exposure to the open-circuit voltage (Voc)of a single module 110, generally no more than a normally non lethallevel of approximately 60V. More advantageously this function can beactivated with a safety button or via a remote management console or anetwork such as the Internet (not shown) for maximum flexibility. Thisfunction can also be tied into the buildings existing safety system soit can be automatically activated in the case of an emergency.Consequently the system can be installed, maintained or approached bypersonnel (including fire or other emergency personnel) without exposureto voltage levels which, in some topologies of conventional arraystypically exceed 400 volts during peak operation.

Finally, because each PV module 110 can be controlled individually bythe management modules, it is possible to link and interconnect longerruns of PV modules that span more than one face of the building. Whilethe present description presents the TIGO unit as an example it shouldbe understood that the invention is not limited to any particularcontrol module.

While the management modules 135 are shown within the power/controlraceway 130, it is expected that future generations of integrationmodules will continue to shrink in size and therefore can be placed in avariety of locations. For example it will be apparent that they can belocated in other areas of the curtain wall element 105″, includingdirectly on the PV module 110 or directly within the framing members,the wiring channels, or potentially embedded in PV Modules 110. However,it should be noted that there is a benefit in most cases to locating themanagement modules within the power/control raceways because in thisway, the signal lines are better isolated and easily routed betweenpairs of adjacent management modules.

The opening for the PV module leads 140 preferably includes a grommet145 on the inboard vertical surface of the horizontal framing member150. This allows for the PV module leads (or other conduits, tubes,etc.) 140 to exit the framing member 150 and enter the power/controlraceway 130 in a safe and secure fashion, and in a manner that resistsaging, corrosion, and damage from movement that may be cause byearthquakes, wind, etc. Skilled artisans will appreciate that theadditional space shown within framing member 150 that is not used in theembodiment shown in FIG. 2, could be used in some applications to routeelectrical wiring or alternative form factors of management module 135.Again also in other embodiments of the invention (using other forms ofconversion devices or solar heat collectors) additional tubing,conduits, etc., could be routed within this part of the framing membersand used to transport heat energy in the form of a conductible fluid,gas, air, etc. to other areas of the building structure.

Again, one preferred aspect of the present invention is to ensure ULand/or CSA/TUV/ETL compliance. The curtain wall units 105 andpower/control raceways 130 of the preferred embodiment further servesuch aim by including the capacity to handle regulatory rated cabling,and with mountings (i.e., appropriate hole sizing, grommets and othertethering/tieing mechanism) and cable runs/shielding that allow forappropriate separation of different types of signal cables, such as highand low power lines, that are also designed to satisfy applicableregulations.

Note as shown in FIG. 1 the floor level in the preferred embodiment issomewhat below the bottom of the horizontal framing member 150, but,this can be altered as desired in any particular installation.Power/control raceway 130 is also preferably designed to beUL-compliant, reducing duration of work on site, construction costscertification expense and commission expenditures. To this end theraceway may be comprised of materials well-known in the art.

The rest of the curtain wall unit 105″ is shown with conventional visionmaterial elements 115, and various gaskets—for example, wedge gasket165, and bed gasket 170, to help in securing and isolating the PV module110 from the curtain wall unit 105′. Note that these same types ofgaskets are also shown but not annotated specifically in the deepglazing pocket region 125. The gaskets are preferably comprised ofmaterials that are UL rated for this purpose and may vary frominstallation to installation.

FIG. 3 shows a plan view of a curtain wall along the horizontalaxis/direction shown in FIG. 1 with the annotation/label having a circlewith the number three (3). This perspective is shown between twoadjacent curtain wall units 105′ and 105.″

In particular it can be seen that the PV modules 110 are preferablyinsulated and isolated by a set of gaskets 165, 170 as noted before inFIG. 2. As is known in the art, the use of such gaskets accommodatesnormal material expansions/contractions, and allows for flexibility andmovement of the panels, such as needed for wind, seismic and otherdisturbances. While gaskets are illustrated as the isolating mechanismin the preferred embodiment (including for electrical isolation), itwill be noted that other materials could be used, including structuralsilicones or VHB tape, such as that sold by 3M (Minnesota Mining andManufacturing) without parting from the scope of the invention.

The main feature of FIG. 3 is a vertical framing member 155, the top ofwhich is shown in this plan view. This framing member, like thehorizontal framing member 150 noted earlier, is preferably formed fromthe spaces created in the mating or coupling of the individual curtainwall units 105, and preferably without requiring additional separatestructures or materials. As with its counterpart this member hasadditional space that can be used to accommodate other types of conduitsas needed by particular energy conversion devices.

An additional structure, namely an integral vertical wiring managementclip 160 is also included as part of the curtain wall unit 105″. Thisclip effectively behaves as a vertical conduit to accept, manage andintegrate the power and signal cables from PV modules 110, allowing themto be interconnected in a vertical orientation as well. Thus, as seen inFIG. 1, the PV modules 120 in a vision area can be coupled directly toPV modules 110 in a spandrel area, or even to other modules in aspandrel area below vision area 120, and so on. The use of both verticaland horizontal wire accepting frame members allows for PV modules to beconnected in a checkerboard fashion, both in the vertical and horizontaldirection, to form a larger array across the face of the buildingstructure and even across separate faces of the building structure.

Note that the shape and form of the clip 160 is illustrated in thepreferred embodiment as a solid rectangular box structure in FIG. 3, butany number of variants could be used to accommodate the power/signalcables. Additional conduits could also be incorporated (including on theopposite curtain wall element 105′) as desired for any application.While the conduits are shown in a closed configuration (which permitseasy threading/routing of the cables) it will be apparent that otherstructures could be used. For example the wiring may also beprefabricated or built into the curtain wall unit 105, (for examplealong the edge of the vertical framing member). Such wiring wouldpreferably connect with an electrical coupler to PV module leads 140. Atthe other end of the framing member a corresponding electrical couplercould be used to connect to the leads from a second PV module, or,alternatively, to leads extending to a management module 135. Any numberof similar variants are possible, and the invention is not limited inthis respect.

As with the other elements of the curtain wall unit 105″ the verticalwiring management clip 160 is preferably constructed in a UL compliantmanner to permit installation of the units without additional regulatoryapproval or accompanying delays.

FIG. 4 is a plan view again along the horizontal direction shown in FIG.1 with the bubble label containing the number 4. This figure is acut-away and illustrates more of the details of the power/controlraceway 130 used in preferred embodiments of the present invention(s).

The power/control raceway 130 is another feature unique to the presentinvention. Though similar in function to existing technology, thepower/control raceway 130 is unique in that it may also be used formultiple purposes: as a conduit to carry the managementmodule-management module cabling 165 (or other tubing/conduits), tocontain management module 135, and to serve as an interior architecturaltrim piece. While not shown in FIG. 4, the power/control raceway alsopreferably includes a grommeted hole and access for a connector on theunderside (bottom) as seen in FIG. 2 for receiving the leads 140 fromthe PV modules. Again the location of the connector is not critical, andthe cabling/coupling is expected to be accomplished in any number ofdifferent ways.

Returning to FIG. 4 the power/control raceway 130 is preferably formedseparately in a predetermined length and then integrated as an assemblyon part of the backside of a curtain wall unit 105 after unitinstallation on the structure. This enables each curtain wall unit 105to effectively act as a unitized building block for constructing a solararray when integrated with the power/control raceway 130 as part of abuilding façade without additional supporting elements. In someembodiments the power/control raceway can be implemented in a similarmanner in the vertical direction.

The power/control raceway 130, as with the other curtain wall elements,is in the preferred embodiment is to be rated for UnderwritesLaboratories (UL) or similar organization compliance and is made ofaluminum or some other cost effective materials.

The management modules 135 are located in the power/control raceway 130and manage/control/communicate with the individual PV modules. Thesemanagement modules preferably optimize power output per each PV moduleand exchange operational management and performance monitoring data,allowing remote manipulation/management of the array.

The PV module leads 140 are coupled between the PV modules and themanagement modules to transmit generated power and communicate otherstatus information to and from the modules. It will be understood thatthe particular coupling, wiring, etc., is expected to vary betweendifferent types PV modules or energy conversion devices.

Management module to module cabling 165 carries the accumulated power toa management unit 680 (See FIG. 6). The management unit is preferably aTIGO Energy™ Maximizer Management Unit (MMU) that manages the wholeassembly by processing the individual and aggregated information fromthe PV modules. In a preferred embodiment, the management unit iscapable of managing an entire set of management modules 635 for abuilding and/or an array. The management unit communicates between themanagement modules 635 and an Inverter 690 which is a modified typicalcomponent of any solar power generation system. Inverter 690 inverts DCto AC as known in the art. The management unit (680) preferably controlsthe management modules in real time and sends data to a remote server695 in order to allow on or offsite monitoring of light, temperature,electricity production and other parameters and provides the resultinginformation as needed. Again the monitoring system architecture will bea function of the particular energy generation mechanism selected, andit is expected that other variants of the above will be used withdifferent energy conversion systems.

Returning to FIG. 4, this also shows a bonding jumper 175, which is usedto connect the individual curtain wall elements to each other, and,eventually, to a ground potential such as the steel frame, or otherconventional common grounding element in the building electrical system(not shown). In the preferred embodiment grounding is accomplished byany of the means known in the art.

Note that a portion of the vertical framing members 155 can be seen inFIG. 4 as well. The routing of PV module leads 140 into such framingmembers is also shown in more detail in FIG. 5. FIG. 5 shows a crosssection of the building in FIG. 1, along the bubble annotated with thenumber five (5). As shown in FIG. 5, the PV module leads 140 preferablyextend from the top of a PV module 180; they are routed through grommet145, and then into the horizontal framing member 150; and then they arerouted to the vertical framing member 155, and thus can be transported(up or down) through the vertical wiring management clip 160.

FIGS. 8A and 8B show another perspective view of the mullions formed bya pair of adjacent curtain wall elements 105. The additional space 190formed within the mullion is usable as noted earlier for other arrayelements as needed. All other labeled elements are the same as likenumbered items discussed in earlier figures.

An electrical diagram showing the main preferred components of a solarpower generation system is shown in FIG. 6. In this figure, likenumbered elements are intended to correspond to their counterparts inprior figures unless otherwise noted.

As seen in FIG. 6 an array of PV modules 610/620 are preferably coupledto each other through the management module 635. The connections betweenthe PV modules and the management modules are preferably done throughthe PV leads 640 that are routed both vertically and horizontallythrough framing members 650 and 655 respectively as noted earlier. Themanagement modules 635 are themselves preferably connected throughcabling 665, and eventually to a management unit 680 as noted above. Thewiring for these connections, are preferably done with power/controlraceways 630 that are integrated with the curtain wall units 605.

In the preferred embodiment, management unit 680 is in turn preferablycoupled to a DC disconnect 685. As noted above, DC disconnect maypreferably be activated either manually or electronically to isolatepower to the output of the individual PV module. The output of this DCdisconnect is preferably coupled to an inverter 690 which converts theDC generated voltage into an AC voltage in a well-known manner. Notethat the management unit 680 is shown outside of the curtain wall unit105, but it could be included within that unit without departing fromthe scope of the present invention.

The preferred embodiment includes a monitoring system 692 can be used toevaluate the performance of the individual PV modules 610 throughinterrogation of their respective management modules 635. The monitoringsystem includes conventional computing equipment and software forcoordinating data exchanges, calculations, etc., with the managementunit and management modules as is known in the art. Preferably thecomputing system is a server that is Internet accessible for remoteaccess.

The output of the array is preferably connected to the buildingelectrical system, typically in the main distribution area, where it canbe used to offset consumption of electrical power or feed power into theutility grid. In some instances the array can offer other DC and ACoutlets for charging electrical devices, transportation vehicles, etc.The form of the output, including voltage levels, current levels, etc.,can be tailored as needed for any particular application. Furthermore ifdesired a conventional electrical storage system 691 can be employed insome cases to provide back-up power if desired. Again it will beunderstood that the support elements for a particular power generationsystem will vary according to the energy conversion devices used, andFIG. 6 is merely depicting the typical elements that would be used in asolar to electrical conversion system.

FIG. 7 is a flowchart illustrating the general steps employed in apreferred PV solar system assembly process. At step 710, the curtainwall elements 105 are preferably hung on a building structure in amanner effectively identical to that used in conventional curtain wallsystems with the differences described above.

At steps 715 and 720 the PV module leads are then preferably routed bothhorizontally and vertically as needed through framing members 150 and155 respectively integrated within the curtain wall units 105. Thisallows for flexible interconnection of adjacent PV modules in the solararray.

During step 725 the PV module leads 140 are preferably connected tomanagement modules 135 through connectors contained in horizontalframing member 150. At step 730 the individual management modules arealso preferably electrically coupled together using themanagement-module-to-management module cabling 165 in the power/controlraceway 130.

The grounding can be achieved during any one or more of the above stepsin the manner known in the art. At this point the entire assembly,consisting of unitized curtain wall elements interconnected to form asolar array, is also completely safe and preferably UL compliant.

At step 735 the integration module 135 outputs are preferably connectedto one or more management unit 680 as described earlier. At step 740,the electrical power can then be conveniently transferred to thebuilding electrical distribution system, or made available through otheroutputs for other applications (charging). It will be apparent the abovesteps do not have to be performed in the sequence noted, and that theactual assembly process will likely include other obvious variants ofthe above.

To summarize, it can be seen that the invention implements a new type ofPV capable curtain wall unit that has been specifically designed andengineered to be a power generator, but accomplishes a dual purpose: toenclose the building aesthetically as part of the outermost exteriorshell enveloping the bulk of the building façade. Summing up, in thepreferred embodiment, this is achieved by, among other things:

-   -   extra deep glazing pockets incorporated in curtain wall units    -   adapting the framing members to include UL and other compliant        conduits, channels and raceways for wiring    -   housing control and management mechanisms locally, in each unit    -   Including control needed to eliminate the deleterious effect of        on-site/orientation shaded unit from others    -   electrically isolating the PV modules with the use of code        compliant sealants and gaskets    -   the addition of ports and isolating grommets to facilitate        electrical connections and contain control mechanisms in the        framing members    -   framing members with flexible parts/sleeves to accommodate        movement (for example in response to a seismic events) without        damage to the electrical wiring

As such, virtually all of the components of conventional curtain wallunits are adapted to deliver solar generated power as part of a PVsystem which is constituted substantially within an exterior aestheticshell.

UL Compliance/Other Third Party Organizations

Unlike prior art systems, preferred embodiments of the invention thusefficiently achieve UL compliance as built because:

-   -   each unit is grounded;    -   wiring and associated control devices are housed in a        pre-certified raceway (for example, inner cavities of the        framing members); and    -   electrical isolation is provided between the PV panels and their        framing/surrounding elements (via the sealants and gaskets—that        are manufactured from code-rated materials).        Retrofits:

Embodiments of the invention can also be used for an existing buildingor structure which can be retrofitted or re-clad to incorporate othervariants of the invention. Moreover in some instances, the PV modulescan be integrated into curtain wall units in an array suitable formounting on mechanical screening or other vertical faces (not shown)typically found on a building or structure. By utilizing such previouslyunproductive space, the invention can add value to existing propertiesby making them more cost-effective, attractive to environmentallyconscious tenants, and so on.

As alluded to above the present invention can also be used withadditional PV enhancement devices, such as solar concentrators, solartrackers (active and passive) and the like (not shown). Particularly inthe spandrel areas, where appearance is not as critical, the integrationof solar concentrators/trackers within the curtain wall elements couldbe used to greatly increase the collection of solar flux, by altering aradiation path to make it more incident to the elements, or adjustingthe orientation of the elements themselves.

While not explicitly shown or described herein, the details of thevarious software routines, executable code, firmware, etc., required toeffectuate the functionality discussed above in the management modules,management units and monitoring systems are not material to the presentinvention, and may be implemented in any number of ways known to thoseskilled in the art. Such code, routines, etc. may be stored in anynumber of forms of machine readable media.

The above descriptions are intended as merely illustrative embodimentsof the proposed inventions. It is understood that the protectionafforded the present invention also comprehends and extends toembodiments different from those above, but which fall within the scopeof the present claims.

1. A building integrated photovoltaic power generating systemcomprising: a plurality of unitized curtain wall units adapted as partof an exterior shell for a building structure; said unitized curtainwall units being adapted to be hung from and situated in front of saidbuilding structure and including vertical areas formed of glazing and/orcladding materials; wherein at least one such unitized curtain wall unitincludes vertical and horizontal framing members defining a plurality ofglazing areas in both vision and spandrel areas; wherein at least two ofsaid plurality of glazing areas, including both said vision and spandrelareas each contain one or more integrated photovoltaic conversiondevices; further said integrated photovoltaic conversion devices in saidvision areas are of a first type having a first power performancecharacteristic, and integrated photovoltaic conversion devices in saidspandrel areas are of a second type having a second power performancecharacteristic that is different from said first power performancecharacteristic; said integrated photovoltaic conversion devices beingelectrically connected to control units integrated within said unitizedcurtain wall unit; wherein said unitized curtain wall units form aphotovoltaic power generating array.
 2. The building integrated powergenerating system of claim 1 wherein a plurality of control units areintegrated within said unitized curtain wall units; said control unitseach optimizing a power output of at least one of said plurality ofphotovoltaic energy conversion modules.
 3. The building integrated powergenerating system of claim 1 wherein said plurality of control unitsmitigate the effect of shading on said integrated photovoltaicconversion devices.
 4. The building integrated power generating systemof claim 1 wherein said plurality of integrated photovoltaic conversiondevices are included in at least 25% of said vision areas.
 5. Thebuilding integrated power generating system of claim 4 wherein saidplurality of second energy conversion modules are included in at least50% of said spandrel areas.
 6. The building integrated power generatingsystem of claim 1 wherein said unitized curtain wall units span avertical space that extends and covers a continuous strip of visionareas and contiguous spandrel areas over multiple stories of thebuilding structure.
 7. The building integrated power generating systemof claim 1 said integrated photovoltaic conversion devices in saidvision areas are arranged with a first spatial density, and integratedphotovoltaic conversion devices in said spandrel areas are arranged witha second spatial density that is different from said first spatialdensity.
 8. The building integrated power generating system of claim 1wherein a power output per unit area differs in said vision areas andspandrel areas.
 9. The building integrated power generating system ofclaim 1 wherein said plurality of unitized curtain wall units mate withadjacent vertical and horizontal counterpart unitized wall elements soas to seal said shell from air and water intrusions.
 10. The buildingintegrated power generating system of claim 1 wherein the plurality ofinterconnected unitized curtain wall units meet Underwriter Laboratories(UL) or other applicable local regulatory requirements associated withthe building for building integrated power generation systems and doesnot require a separate inspection prior to operation.
 11. The buildingintegrated power generating system of claim 1 wherein said unitizedcurtain wall units include: a) both vertical and horizontal framingmembers adapted to support a module associated with said photovoltaicenergy conversion devices; b) support brackets adapted to affix theunits to a building floor slab; and c) sealants and/or gaskets adaptedto connect and isolate said devices.
 12. A building integratedphotovoltaic power generating system comprising: a plurality of unitizedcurtain wall units adapted as part of an exterior shell for a buildingstructure; said unitized curtain wall units being adapted to be hungfrom and situated in front of said building structure and includingvertical areas formed of glazing and/or cladding materials; wherein atleast one such unitized curtain wall unit includes vertical andhorizontal framing members defining a plurality of glazing areas in bothvision and spandrel areas; wherein at least two of said plurality ofglazing areas, including both said vision and spandrel areas eachcontain one or more integrated photovoltaic conversion devices; whereinsaid integrated photovoltaic conversion devices in said vision areas arearranged with a first spatial density, and integrated photovoltaicconversion devices in said spandrel areas are arranged with a secondspatial density that is different from said first spatial density; saidintegrated photovoltaic conversion devices being electrically connectedto control units integrated within said unitized curtain wall unit;wherein said unitized curtain wall units form a photovoltaic powergenerating array.
 13. A building integrated photovoltaic powergenerating system comprising: a plurality of unitized curtain wall unitsadapted as part of an exterior shell for a building structure; saidunitized curtain wall units being adapted to be hung from and situatedin front of said building structure and including vertical areas formedof glazing and/or cladding materials; wherein at least one such unitizedcurtain wall unit includes vertical and horizontal framing membersdefining a plurality of glazing areas in both vision and spandrel areas;wherein at least two of said plurality of glazing areas, including bothsaid vision and spandrel areas each contain one or more integratedphotovoltaic conversion devices; said integrated photovoltaic conversiondevices being electrically connected to control units integrated withinsaid unitized curtain wall unit and being configured such that a poweroutput per unit area differs in said vision areas and spandrel areas;wherein said unitized curtain wall units form a photovoltaic powergenerating array.